From patchwork Mon Dec 5 11:57:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kemeng Shi X-Patchwork-Id: 13064117 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2ECAC636F8 for ; Mon, 5 Dec 2022 03:58:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231438AbiLED6F (ORCPT ); Sun, 4 Dec 2022 22:58:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231213AbiLED6B (ORCPT ); Sun, 4 Dec 2022 22:58:01 -0500 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7B80FD10; Sun, 4 Dec 2022 19:57:58 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4NQVBS3Tsgz4f3kpT; Mon, 5 Dec 2022 11:57:52 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP1 (Coremail) with SMTP id cCh0CgDXfq1CbI1jRaRVBg--.57323S3; Mon, 05 Dec 2022 11:57:55 +0800 (CST) From: Kemeng Shi To: tj@kernel.org, josef@toxicpanda.com, axboe@kernel.dk Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, shikemeng@huawei.com, linfeilong@huawei.com, liuzhiqiang26@huawei.com Subject: [PATCH v3 1/9] blk-throttle: correct stale comment in throtl_pd_init Date: Mon, 5 Dec 2022 19:57:01 +0800 Message-Id: <20221205115709.251489-2-shikemeng@huaweicloud.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20221205115709.251489-1-shikemeng@huaweicloud.com> References: <20221205115709.251489-1-shikemeng@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: cCh0CgDXfq1CbI1jRaRVBg--.57323S3 X-Coremail-Antispam: 1UD129KBjvJXoW7KFyUCr1xAF43KrWxJF45trb_yoW8Xr1kpr y3uF18KFsxWa1jkr4rZ3WfZayrur48KrW5Zr98Aw43JrW3K34DGF1avrW0q3ZavF1fKrs0 vF12ya4xJ3WUC3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBjb4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUGwA2048vs2IY020Ec7CjxVAFwI0_JFI_Gr1l8cAvFVAK 0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4 x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2 z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4 xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v2 6r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x0EwI xGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480 Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7 IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k2 6cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxV AFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07jsIDcUUUUU= X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Kemeng Shi On the default hierarchy (cgroup2), the throttle interface files don't exist in the root cgroup, so the ablity to limit the whole system by configuring root group is not existing anymore. In general, cgroup doesn't wanna be in the business of restricting resources at the system level, so correct the stale comment that we can limit whole system to we can only limit subtree. Signed-off-by: Kemeng Shi Acked-by: Tejun Heo Signed-off-by: Kemeng Shi --- block/blk-throttle.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 847721dc2b2b..8e2349b17936 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -395,8 +395,9 @@ static void throtl_pd_init(struct blkg_policy_data *pd) * If on the default hierarchy, we switch to properly hierarchical * behavior where limits on a given throtl_grp are applied to the * whole subtree rather than just the group itself. e.g. If 16M - * read_bps limit is set on the root group, the whole system can't - * exceed 16M for the device. + * read_bps limit is set on a parent group, summary bps of + * parent group and its subtree groups can't exceed 16M for the + * device. * * If not on the default hierarchy, the broken flat hierarchy * behavior is retained where all throtl_grps are treated as if